Can you please take a whole plant picture with the grow lights off?
Very often Calcium deficiency is caused by issues with other nutrients, so a picture of the entire plant can help rule that out. It'd help to know what other nutrients besides the Cal-Mag you're using, and at what levels you're mixing it for even better analysis.
Botanicare Cal-Mag Plus uses Calcium Nitrate as the Ca source, which is why it has 2% Nitrogen in it. I draw my water from the lake I live on, so the PPM is extremely low (55-65 PPM), so I have to add Cal-Mag at all times (especially because I'm growing in Sunshine #4 which is inert) when I lower the amount of Calcium Nitrate I mix into my nutrient stock tanks for the flowering plants. I use 4.5mL per gallon, so a little more than your 1mL per Litre (a gallon is 3.89 Litres).